A conventional shelf includes connections and panels compose together to form a frame of a receiving space, which can provide storage function for the users. However, the storage space for conventional shelves is most likely rectangle, and if the user wants to increase the storage space, he/she can only stack up the shelves. Moreover, it is not adjustable, less practical, without the stability of structural strength, which may decrease the user's interest of purchasing the product. Therefore, there remains a need for a new and improved shelf interlayer structure to overcome the problems stated above.